1. Field of the Invention
The present invention relates to novel absorbates with a special composition, in particular a high loading of particular substances for use in plant protection compositions, the use of a special process for the preparation of the absorbates and products for plant protection comprising the absorbates.
2. Description of the Related Art
In the field of products for plant protection, a distinction is made between solid and liquid formulation types. In the field of solid formulations, liquid or meltable active substances, together with auxiliaries (for example, surfactants and disintegrating agents), are attached to carrier materials. With solid active substances, the carrier materials serve firstly as fillers. With liquid or low melting point active substances the carriers serve to absorb the liquid or low melting point active substances. Superficially dry absorbates are obtainable which are easy to handle and which maybe marketed either directly as powders (WP, wettable powder) or, processed, as granules/extrudates (WG, water dispersible granules).
In the case of WGs, a pre-prepared absorbate powder may be converted to a granule form or the product components maybe formed directly (for example, by spray drying). A possible preparation of WGs by direct spray drying of a dispersion of silica, active substance and additional auxiliaries is disclosed, for example, in U.S. Pat. No. 6,869,914.
In particular with liquid or low melting point active substances and auxiliaries for plant protection compositions, subsequently referred to as “particular substances for use in plant protection compositions”, it is impossible with the processes known to date to prepare absorbates with a desired high content of particular substances for use in plant protection compositions. Thus, using conventional processes, absorbates with satisfactory flowability can be prepared only up to 65% by weight based on the total weight of the absorbate (based on a liquid density of 1.00 g/ml).
In mechanical absorption processes, such as, for example, simple mixing of the components, a very broad distribution in the size of the agglomerates of the absorbates is to be expected in the region of the limit load of the silica. This tends to greatly reduce the flowability of the resulting products and aggravates further handling (metering, and the like). In addition, in conventional mixing processes it is difficult to avoid compacting agglomeration. Such compacting agglomerates are undesirable, for example when the product is used as WP, since they have a negative effect on the desired good disintegration behavior on redispersing in water.
Additional disadvantages of the absorbates of the state of the art are a sometimes expensive preparation process and in particular a high proportion of expensive carrier materials, which also include carrier material silicas. In products for plant protection in particular, which are produced and sold in very large amounts, even a small reduction in the amounts of the carrier materials used would already be tremendously advantageous economically and also ecologically.